The enzyme dipeptidyl peptidase IV (EC.3.4.14.5, abbreviated in the following as DPP-IV) is involved in the regulation of the activities of several hormones. In particular DPP-IV is degrading efficiently and rapidly glucagon like peptide 1 (GLP-1), which is one of the most potent stimulator of insulin production and secretion. Inhibiting DPP-IV would potentiate the effect of endogenous GLP-1, and lead to higher plasma insulin concentrations. In patients suffering from impaired glucose tolerance and type 2 diabetes mellitus, higher plasma insulin concentration would moderate the dangerous hyperglycaemia and accordingly reduce the risk of tissue damage. Consequently, DPP-IV inhibitors have been suggested as drug candidates for the treatment of impaired glucose tolerance and type 2 diabetes mellitus (e.g. Vilhauer, WO98/19998). Without disclosing any medical use, Buzas et al., Lab. Chim. Org. V, Fac. Sci., Orleans, Fr. Chim. Ther. (1992), 7(5), 404-7 describe synthesis of the compounds of Examples 41 and 42 below.
The compounds of the present invention are useful for the treatment and/or prophylaxis of diabetes or non-insulin dependent diabetes.
The present invention provides pyrido[2,1-a]isoquinoline derivatives in accordance with formula (I) 
wherein
R1 is lower alkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, or lower alkyl substituted by cycloalkyl, aryl, substituted aryl, heteroaryl or substituted heteroaryl;
R2, R3 and R4 are each independently hydrogen, halogen, hydroxy, lower alkyl, lower alkoxy or lower alkenyl, wherein lower alkyl, lower alkoxy and lower alkenyl are optionally substituted by lower alkoxycarbonyl, aryl, substituted aryl, heterocyclyl or substituted heterocyclyl;
R5 is hydrogen, fluorine, lower alkyl, aryl or substituted aryl;
R6 is hydrogen, lower alkyl or hydroxy-lower alkyl, or
R5 and R6 together with the carbon atoms to which they are attached form a five or six membered saturated carbocyclic ring;
R7 is hydrogen, fluorine or lower alkyl;
and pharmaceutically acceptable salts thereof;
with the exception of rac-3xcex2-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine dihydrochloride and rac-3xcex2-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine dihydrochloride.
Novel DPP-IV inhibitors have been found that very efficiently lower plasma glucose levels. Consequently, the compounds of the present invention are useful for the treatment and/or prophylaxis of diabetes, particularly non-insulin dependent diabetes mellitus, and/or impaired glucose tolerance, as well as other conditions wherein the amplification of action of a peptide normally inactivated by DPP-IV gives a therapeutic benefit. Surprisingly, the compounds of the present invention can also be used in the treatment and/or prophylaxis of Bowl disease, Colitis Ulcerosa, Morbus Crohn, obesity and/or metabolic syndrome. Furthermore, the compounds of the present invention can be used as diuretic agents and for the treatment and/or prophylaxis of hypertension. Unexpectedly, the compounds of the present invention exhibit improved therapeutic and pharmacological properties compared to other DPP-IV inhibitors known in the art, such as e.g. in context with pharmacokinetics and bioavailability.
The present invention provides pyrido[2,1-a]isoquinoline derivatives in accordance with formula (I) 
wherein
R1 is lower alkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, or lower alkyl substituted by cycloalkyl, aryl, substituted aryl, heteroaryl or substituted heteroaryl;
R2, R3 and R4 are each independently hydrogen, halogen, hydroxy, lower alkyl, lower alkoxy or lower alkenyl, wherein lower alkyl, lower alkoxy and lower alkenyl are optionally substituted by lower alkoxycarbonyl, aryl, substituted aryl, heterocyclyl or substituted heterocyclyl;
R5 is hydrogen, fluorine, lower alkyl, aryl or substituted aryl;
R6 is hydrogen, lower alkyl or hydroxy-lower alkyl, or
R5 and R6 together with the carbon atoms to which they are attached form a five or six membered saturated carbocyclic ring;
R7 is hydrogen, fluorine or lower alkyl;
and pharmaceutically acceptable salts thereof;
with the exception of rac-3xcex2-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine dihydrochloride and rac-3xcex2-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine dihydrochloride.
Unless otherwise indicated, the following definitions are set forth to illustrate and define the meaning and scope of the various terms used to describe the invention herein. In this specification the term xe2x80x9clowerxe2x80x9d is used to mean a group consisting of one to six, preferably of one to four carbon atom(s).
The term xe2x80x9chalogenxe2x80x9d refers to fluorine, chlorine, bromine and iodine, preferably to chlorine.
The term xe2x80x9calkylxe2x80x9d, alone or in combination with other groups, refers to a branched or straight-chain monovalent saturated aliphatic hydrocarbon radical of one to twenty carbon atoms, preferably one to sixteen carbon atoms, more preferably one to ten carbon atoms.
The term xe2x80x9clower-alkylxe2x80x9d, alone or in combination with other groups, refers to a branched or straight-chain monovalent alkyl radical of one to six carbon atoms, preferably one to four carbon atoms. This term is further exemplified by radicals such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, n-pentyl, 3-methylbutyl, n-hexyl, 2-ethylbutyl and the like.
The term xe2x80x9ccycloalkylxe2x80x9d refers to a monovalent carbocyclic radical of three to six carbon atoms. This term is further exemplified by radicals such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl, with cyclopropyl being preferred.
The term xe2x80x9calkoxyxe2x80x9d refers to the group Rxe2x80x2xe2x80x94Oxe2x80x94, wherein Rxe2x80x2 is alkyl. The term xe2x80x9clower-alkoxyxe2x80x9d refers to the group Rxe2x80x2xe2x80x94Oxe2x80x94, wherein Rxe2x80x2 is lower-alkyl. Examples of lower-alkoxy groups are e.g. methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy and hexyloxy, with methoxy being especially preferred.
The term xe2x80x9clower alkoxycarbonylxe2x80x9d refers to the group Rxe2x80x2xe2x80x94Oxe2x80x94C(O)xe2x80x94, wherein Rxe2x80x2 is lower alkyl.
The term xe2x80x9cheterocyclylxe2x80x9d refers to a 5- or 6-membered aromatic or saturated N-heterocyclic residue, which may optionally contain a further nitrogen or oxygen atom, such as imidazolyl, pyrazolyl, thiazolyl, phenyl, pyridyl, pyrimidyl, morpholino, piperazino, piperidino or pyrrolidino, preferably pyridyl, thiazolyl or morpholino. The term xe2x80x9csubstituted heterocyclylxe2x80x9d refers to a heterocyclyl that is mono-, di- or tri-substituted, independently, by lower alkyl, lower alkoxy, halo, cyano, azido, amino, di-lower alkyl amino or hydroxy. Preferable substituent is lower alkyl, with methyl being preferred.
The term xe2x80x9carylxe2x80x9d refers to an aromatic monovalent mono- or polycarbocyclic radical, such as phenyl or naphthyl, preferably phenyl. The term xe2x80x9csubstituted arylxe2x80x9d refers to an aryl that is mono-, di- or tri-substituted, independently, by lower alkyl, lower alkoxy, halo, cyano, azido, amino, di-lower alkyl amino or hydroxy.
The term xe2x80x9cheteroarylxe2x80x9d refers to a 5- or 6-membered, unsaturated aromatic monovalent cyclic radical containing one to three, preferably one or two, heteroatoms independently selected from nitrogen, sulfur and oxygen, with nitrogen being preferred. Examples of heteroaryl residues are pyrrolyl, pyridinyl and pyrimidinyl, with pyrrolyl and pyridinyl being preferred. The term xe2x80x9csubstituted heteroarylxe2x80x9d refers to a heteroalkyl that is mono-, di- or tri-substituted, independently, by halogen, amino, perfluoro-lower alkyl, lower alkyl or lower alkoxy.
The term xe2x80x9cpharmaceutically acceptable saltsxe2x80x9d embraces salts of the compounds of formula (I) with inorganic or organic acids such as hydrochloric acid, hydrobromic acid, nitric acid, sulphuric acid, phosphoric acid, citric acid, formic acid, maleic acid, acetic acid, fumaric acid, succinic acid, tartaric acid, methanesulphonic acid, salicylic acid, p-toluenesulphonic acid and the like, which are non toxic to living organisms. Preferred salts with acids are formates, maleates, citrates, hydrochlorides, hydrobromides and methanesulfonic acid salts, with hydrochlorides being especially preferred.
In one embodiment, the present invention relates to a compound of formula (I) as defined above, wherein R1 is lower alkyl, aryl, substituted aryl, or lower alkyl substituted by cycloalkyl, aryl or substituted aryl; R2, R3 and R4 are each independently hydrogen, hydroxy, lower alkyl, lower alkoxy or lower alkenyl, wherein lower alkyl, lower alkoxy and lower alkenyl may optionally be substituted by lower alkoxycarbonyl, aryl, substituted aryl, heterocyclyl or substituted heterocyclyl; R5 and R6 are each independently hydrogen, lower alkyl, aryl, substituted aryl, or, together with the carbon atoms to which they are attached form a five or six membered saturated carbocyclic ring; and pharmaceutically acceptable salts thereof.
In another embodiment, the present invention relates to a compound of formula (I) as defined above, wherein R1 is lower alkyl, phenyl, or cycloalkyl-lower alkyl; R2, R3 and R4 are each independently hydrogen, hydroxy, lower alkoxy; or lower alkoxy substituted by aryl, substituted aryl, heterocyclyl, substituted heterocyclyl, or lower alkoxycarbonyl. Preferable aryl or substituted aryl residues in R2, R3 and R4 are phenyl or phenyl substituted by di-lower alkyl amino or cyano. Preferable heterocyclyl or substituted heterocyclyl residues in R2, R3 and R4 are morpholino, pyridyl, thiazolyl or thiazolyl substituted by lower alkyl. Preferable lower alkoxycarbonyl residues in R2, R3 and R4 are ethoxycarbonlymethoxy.
In another preferable embodiment, the present invention relates to a compound of formula (I) as defined above, wherein R1 is lower alkyl, phenyl, phenyl substituted by lower alkyl or by lower alkoxy, or R1 is heteroaryl or substituted heteroaryl, such as where the heteroaryl residue is pyrrolyl and pyridinyl, or cycloalkyl-lower alkyl; R2, R3 and R4 are each independently hydrogen, hydroxy, lower alkoxy; or lower alkoxy substituted by aryl, substituted aryl, heterocyclyl, substituted heterocyclyl, or lower alkoxycarbonyl; R5 is hydrogen, lower alkyl or phenyl mono- or di-substituted by lower alkyl, lower alkoxy or halogen; R6 is hydrogen, lower alkyl or hydroxy-lower alkyl; or R5 and R6 together with the carbon atoms to which they are attached form a five or six membered saturated carbocyclic ring; and R7 is hydrogen or lower alkyl
In one embodiment, residue R1 is lower alkyl or lower alkyl substituted by cycloalkyl, preferably cyclopropyl. Preferable lower alkyl residues R1 are n-propyl, n-butyl, isobutyl, 3-methylbutyl and 2-ethylbutyl, most preferred are n-propyl, n-butyl and 3-methylbutyl.
Preferable lower alkyl substituted by cycloalkyl is cyclopropylmethyl.
In another embodiment, R1 is aryl or substituted alkyl, preferably in which the aryl residue is phenyl. Substituted aryl residues R1 may be mono-, di- or tri-substituted aryl, independently, by lower alkyl, lower alkoxy or hydroxy, preferably by lower alkyl or lower alkoxy. Preferably, aryl residues R1 are unsubstituted.
In still another embodiment, R1 is a heteroaryl or substituted heteroaryl in which the heteroaryl residue is selected from pyridinyl, pyrimidinyl and pyrrolyl. Preferredare pyridinyl or pyrrolyl. Substituted heteroaryl residues R1 may be mono-, di- or tri-substituted heteroaryl, independently, by lower alkyl, lower alkoxy, or hydroxy, preferably by lower alkyl or lower alkoxy. Preferably, heteroaryl residues R1 are unsubstituted.
Most preferred R1 are lower alkyl, preferably n-butyl, or unsubstituted phenyl.
In one preferable embodiment, residue R2 is lower alkoxy, preferably methoxy, hydrogen or hydroxy. Most preferable residue R2 is methoxy.
In another preferable embodiment, residue R3 is lower alkoxy, with methoxy, ethoxy, propoxy, n-butoxy and isobutoxy being preferred, hydrogen, hydroxy; or lower alkoxy, preferably methoxy or ethoxy, substituted by aryl, substituted aryl, heterocyclyl, substituted heterocyclyl, or lower alkoxycarbonyl.
Preferable aryl or substituted aryl substituents in R3 are unsubstituted phenyl or phenyl mono-substituted by di-lower alkyl amino, with dimethylamino being preferred, or by cyano. Most preferable aryl substituents in R3 is unsubstituted phenyl.
More preferable residues R3 are lower alkoxy, preferably methoxy, hydrogen or hydroxy. Most preferred residue R3 is methoxy or hydroxy, with methoxy being especially preferred.
In another preferable embodiment, residue R4 is lower alkoxy, preferably methoxy, hydrogen or hydroxy. Most preferable residue R4 is hydrogen.
In one embodiment, R5 is hydrogen, lower alkyl, with methyl being preferred, or aryl or substituted aryl.
Preferable aryl or substituted aryl residues R5 are unsubstituted phenyl or phenyl mono-, di- or tri-substituted, independently, by lower alkyl, lower alkoxy or halogen. Most preferable aryl residue R5 is unsubstituted phenyl.
In another embodiment, R6 is hydrogen, lower alkyl, with methyl being preferred, or hydroxy-lower alkyl, with 2-hydroxy-ethyl being preferred. Preferably, R6 is hydrogen.
In still another embodiment, R5 and R6 are hydrogen or, together with the carbon atoms to which they are attached, form a six membered saturated carbocyclic ring.
In one embodiment, R7 is hydrogen, in another embodiment R7 is lower alkyl, preferably methyl.
Preferred compounds of formula (I) are those selected from the group consisting of:
rac-9,10-dimethoxy-3xcex2-propyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
rac-9,10-dimethoxy-3xcex2-(3-methyl-butyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a] isoquinolin-2xcex1-ylamine,
rac-3xcex2-cyclopropylmethyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
rac-7xcex2-butyl-11,12-dimethoxy-2,3,4,4a,6,7,8,9,9a,13bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex2-ylamine,
rac-3xcex2-butyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine chlorohydrate (1:2),
rac-9,10-dimethoxy-3xcex2-propyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine chlorohydrate (1:2),
rac-7xcex2-butyl-11,12-dimethoxy-2,3,4,4a,6,7,8,9,9a,13bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex2-ylamine chlorohydrate (1:2),
rac-2xcex2-amino-3xcex2-butyl-10-methoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-9-ol chlorohydrate (1:2),
rac-2xcex1-amino-3xcex2-butyl-10-methoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-9-ol chlorohydrate (1:2),
rac-2xcex2-amino-3xcex2-butyl-10-methoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-9-ol,
rac-2xcex1-amino-3xcex2-butyl-10-methoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-9-ol, and
rac-9,10-dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine,
and pharmaceutically acceptable salts thereof.
Further preferred compounds of formula (I) are those selected from the group consisting of:
rac-9,10-Dimethoxy-3xcex2-pyrrol-1-yl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-9,10-Dimethoxy-3xcex2-p-tolyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
rac-9,10-Dimethoxy-3xcex2-p-tolyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-9,10-dimethoxy-3xcex2-(3,4-dimethyl-phenyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine chlorohydrate (1:2),
rac-9,10-dimethoxy-3xcex2-(3,4-Dimethyl-phenyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine chlorohydrate (1:2),
rac-9,10-Dimethoxy-3xcex2-(3-methoxy-phenyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine chlorohydrate (1:2),
rac-9,10-Dimethoxy-3xcex2-(3-methoxy-phenyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine chlorohydrate (1:2),
rac-9,10-Dimethoxy-3xcex2-pyridin-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine chlorohydrate (1:2),
rac-9,10-Dimethoxy-3xcex2-pyridin-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine chlorohydrate (1:2),
rac-4-(2xcex2-Amino-3xcex2-butyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-7xcex2-yl)-phenol,
rac-3xcex2-Butyl-9,10-dimethoxy-6-methyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine,
rac-3xcex2-Butyl-7xcex2-(4-chloro-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-3xcex2-Butyl-7xcex1-(4-chloro-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-3xcex2-Butyl-7xcex2-(3,4-dimethoxy-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-3xcex2-Butyl-9,10-dimethoxy-7,7-dimethyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-3xcex2-Butyl-9,10-dimethoxy-7,7-dimethyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
rac-7xcex2-Butyl-11,12-dimethoxy-2,3,4,4axcex2,6,7,8,9,9a xcex1,13bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex2-ylamine,
rac-7xcex2-Butyl-11,12-dimethoxy-2,3,4,4axcex26,7,8,9,9axcex113bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex1-ylamine,
rac-3xcex2-Butyl-7xcex1-(3,4-dimethoxy-phenyl)-9,10-dimethoxy-6xcex1-methyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine,
rac-7xcex2-Butyl-11,12-dimethoxy-13b-methyl-2,3,4,4axcex2,8,6,7,8,9,9a,13b-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex2-ylamine,
rac-9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
9,10-Dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
9,10-Dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
(6S)-(2-Amino-3-butyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-6-yl)-methanol,
rac-4-(2xcex2-Amino-3xcex2-butyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-7-yl)-phenol hydrochloride,
rac-4-(2xcex2-Amino-3xcex2-butyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-7xcex2-yl)-phenol hydrochloride,
rac-3xcex2-Butyl-9,10-dimethoxy-6-methyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine hydrochloride,
rac-3xcex2-Butyl-7xcex2-(4-chloro-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine hydrochloride,
rac-3xcex2-Butyl-7xcex1-(4-chloro-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine hydrochloride,
rac-3xcex2-Butyl-7xcex2-(3,4-dimethoxy-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine hydrochloride,
rac-3xcex1-Butyl-7xcex2-(3,4-dimethoxy-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine hydrochloride,
rac-3xcex2-Butyl-7xcex2-(3,4-dimethoxy-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine hydrochloride,
rac-3xcex2-Butyl-7xcex1-(3,4-dimethoxy-phenyl)-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine hydrochloride,
rac-3xcex2-Butyl-9,10-dimethoxy-7xcex2-(4-methoxy-phenyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine hydrochloride,
rac-3xcex2-Butyl-9,10-dimethoxy-7xcex2-(4-methoxy-phenyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine hydrochloride,
rac-3xcex2-Butyl-9,10-dimethoxy-7,7-dimethyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine hydrochloride,
rac-3xcex2-Butyl-9,10-dimethoxy-7,7-dimethyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine hydrochloride,
rac-7xcex2-Butyl-11,12-dimethoxy-2,3,4,4axcex2,6,7,8,9,9axcex1,13bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex2-ylamine hydrochloride,
rac-7xcex2-Butyl-11,12-dimethoxy-2,3,4,4axcex2,6,7,8,9,9axcex113bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex1-ylamine hydrochloride,
rac-3xcex2-Butyl-7xcex1-(3,4-dimethoxy-phenyl)-9,10-dimethoxy-6xcex1-methyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine hydrochloride,
and pharmaceutically acceptable salts thereof.
Further preferred compounds of formula (I) are those selected from the group consisting of:
rac-9,10-dimethoxy-3xcex2-(3-methyl-butyl)-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-7xcex2-butyl-11,12-dimethoxy-2,3,4,4a,6,7,8,9,9a,13bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex2-ylamine,
rac-3xcex2-butyl-9,10-dimethoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine chlorohydrate (1:2),
rac-7xcex2-butyl-11,12-dimethoxy-2,3,4,4a,6,7,8,9,9a,13bxcex2-decahydro-1H-pyrido[1,2-f]phenanthridin-8xcex2-ylamine chlorohydrate (1:2),
rac-2xcex1-amino-3xcex2-butyl-10-methoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-9-ol chlorohydrate (1:2),
rac-2xcex1-amino-3xcex2-butyl-10-methoxy-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-9-ol, and
rac-9,10-dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine,
and pharmaceutically acceptable salts thereof.
Especially preferred compounds of formula (I) are those selected from the group consisting of:
rac-9,10-dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine,
rac-9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
rac-9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
9,10-Dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine, and
9,10-Dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
and pharmaceutically acceptable salts thereof.
Most preferred compounds of formula (I) are those selected from the group consisting of:
9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
9,10-Dimethoxy-3xcex1-phenyl-1,3,4,6,7,11bxcex1-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine,
9,10-Dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex2-ylamine, and
9,10-Dimethoxy-3xcex2-phenyl-1,3,4,6,7,11bxcex2-hexahydro-2H-pyrido[2,1-a]isoquinolin-2xcex1-ylamine,
and pharmaceutically acceptable salts thereof.
Compounds of formula (I) can have one or more asymmetric carbon atoms and can exist in the form of optically pure enantiomers or as racemates. The invention embraces all of these forms.
It will be appreciated, that the compounds of formula (I) in this invention may be derivatised at functional groups to provide derivatives which are capable of conversion back to the parent compound in vivo.
The present invention also relates to a process for the manufacture of compounds of formula (I) as defined above, which process comprises reducing an oxime of formula (II) 
wherein R1, R2, R3, R4, R5, R6 and R7 are as defined above,
optionally followed by conversion into a pharmaceutically acceptable salt thereof.
Hydrogenation of the above oxime of formula II can be performed according to methods known in the art. For example, the reaction can be performed in the presence of a catalyst such as Raney nickel, platin or palladium in an inert solvent, such as ethanol, at a temperature of about 20xc2x0 C. to 80xc2x0 C.
Hydroxy groups in the compounds of formula II can be present in a protected form, for example as a benzyl ether. Such protecting groups can be removed according to processes known in the art, e.g. in case of benzyl ether by catalytic hydrogenation.
Oximes of formula II are known in the art or can be prepared starting from ketones of the formula III by methods known in the art and as exemplified or in analogy thereto.
Compounds of formula (III): 
wherein R1, R2, R3, R4, R5, R6 and R7 are as defined above,
can be prepared by reacting a compound of the formula (IV): 
wherein R2, R3, R4, R5, R6 and R7 are as defined above,
with a compound of the formula (V): 
wherein R1 is as defined above,
or a compound of the formula (VI): 
wherein R1 is as defined above.
Compounds of formula (IV) are known in the art or can be prepared by oxidation of compounds of formula (VIII): 
wherein R2, R3, R4, R5, R6 and R7 are as defined above,
according to methods known in the art and as exemplified or in analogy thereto.
Alternatively, compounds of formula (VII) 
wherein R1, R2, R4, R5, R6 and R7 are as defined above and P represents an amino protecting group;
may be reacted with an alcohol
xe2x80x83Rxe2x80x94OH
wherein R is lower alkyl substituted by aryl, heterocyclyl or lower alkoxycarbonyl;
in the presence of triphenylphosphine and di-t-butyl azodicarboxylate, followed by deprotection.
Alternatively, compounds of formula (III) wherein R1 is aryl or heteroaryl may be prepared by reacting a compound of formula (III) wherein R2, R3, R4, R5, R6 and R7 are as defined above and R1 is hydrogen (R1=H) with an aryl halogenide respectively a heteroaryl halogenide
Rxe2x80x94X
wherein R is aryl or heteroaryl and X is chloride, bromide, iodide or triflate; in the presence of a palladium catalyst like palladium acetate or tetrakis-triphenylphosphine palladium complex, a ligand, like tri-tert-butylphosphine or other phosphines, and a base like sodium tert-butoxide in an inert solvent like tetrahydrofurane at moderate temperature of 20 to 100xc2x0 C. (in analogy to the methods described in J. M. Fox, X. Huang, A. Chieffi, S. L. Buchwald., J. Am. Chem. Soc. 2000, 122, 1360-1370. and M. Kawatsura and J. F. Hartwig, J. Am. Chem. Soc. 1999, 121, 1473-1478).
Preferred amino protecting groups are t-butyloxycarbonyl (Boc), benzyloxycarbonyl (Z) and 9-fluorenylmethyloxycarbonyl (Fmoc), with t-butyloxycarbonyl (Boc) being especially preferred. Deprotection can be performed by methods known in the art.
The invention further relates to compounds of formula (I) as defined above, when manufactured according to a process as defined above.
As described above, the compounds of formula (I) of the present invention can be used as medicaments for the treatment and/or prophylaxis of diseases which are associated with DPP-IV such as diabetes, particularly non-insulin dependent diabetes mellitus, impaired glucose tolerance, Bowl disease, Colitis Ulcerosa, Morbus Crohn, obesity, and/or metabolic syndrome, preferably non-insulin dependent diabetes mellitus and/or impaired glucose tolerance. Furthermore, the compounds of the present invention can be used as diuretic agents or for the treatment and/or prophylaxis of hypertension.
The invention therefore also relates to pharmaceutical compositions comprising a compound as defined above and a pharmaceutically acceptable carrier and/or adjuvant.
Further, the invention relates to compounds as defined above for use as therapeutic active substances, particularly as therapeutic active substances for the treatment and/or prophylaxis of diseases which are associated with DPP-IV such as diabetes, particularly non-insulin dependent diabetes mellitus, impaired glucose tolerance, Bowl disease, Colitis Ulcerosa, Morbus Crohn, obesity, and/or metabolic syndrome, preferably for use as therapeutic active substances for the treatment and/or prophylaxis of non-insulin dependent diabetes mellitus and/or impaired glucose tolerance. Furthermore, the invention relates to compounds as defined above for use as diuretic agents or for use as therapeutic active substances for the treatment and/or prophylaxis of hypertension.
In another embodiment, the invention relates to a method for the treatment and/or prophylaxis of diseases which are associated with DPP-IV such as diabetes, particularly non-insulin dependent diabetes mellitus, impaired glucose tolerance, Bowl disease, Colitis Ulcerosa, Morbus Crohn, obesity, and/or metabolic syndrome, preferably for the treatment and/or prophylaxis of non-insulin dependent diabetes mellitus and/or impaired glucose tolerance, which method comprises administering a compound as defined above to a human being or animal. Furthermore, the invention relates to a method for the treatment and/or prophylaxis as defined above, wherein the disease is hypertension or wherein a diuretic agent has a beneficial effect.
The invention further relates to the use of compounds as defined above for the treatment and/or prophylaxis of diseases which are associated with DPP-IV such as diabetes, particularly non-insulin dependent diabetes mellitus, impaired glucose tolerance, Bowl disease, Colitis Ulcerosa, Morbus Crohn, obesity, and/or metabolic syndrome, preferably for the treatment and/or prophylaxis of non-insulin dependent diabetes mellitus and/or impaired glucose tolerance. Furthermore, the invention relates to the use as defined above, wherein the disease is hypertension or to the use as diuretic agent.
In addition, the invention relates to the use of compounds as defined above for the preparation of medicaments for the treatment and/or prophylaxis of diseases which are associated with DPP-IV such as diabetes, particularly non-insulin dependent diabetes mellitus, impaired glucose tolerance, Bowl disease, Colitis Ulcerosa, Morbus Crohn, obesity, and/or metabolic syndrome, preferably for the treatment and/or prophylaxis of non-insulin dependent diabetes mellitus and/or impaired glucose tolerance. Such medicaments comprise a compound as defined above. Furthermore, the invention relates to the use as defined above, wherein the disease is hypertension or the use for the preparation of diuretic agents.
In context with the methods and uses defined above, the following diseases relate to a preferred embodiment: diabetes, particularly non-insulin dependent diabetes mellitus, impaired glucose tolerance, obesity, and/or metabolic syndrome, preferably non-insulin dependent diabetes mellitus and/or impaired glucose tolerance.
The compounds of formula (I) can be manufactured by the methods given below, by the methods given in the Examples or by analogous methods. Appropriate reaction conditions for the individual reaction steps are known to the person skilled in the art. Starting materials are either commercially available or can be prepared by methods analogous to the methods given below or in the Examples or by methods known in the art.
The following tests were carried out in order to determine the activity of the compounds of formula I.
Activity of DPP-IV inhibitors are tested with natural human DPP-IV derived from a human plasma pool or with recombinant human DPP-IV. Human citrate plasma from different donors is pooled, filtered through a 0.2 micron membrane under sterile conditions and aliquots of 1 ml are shock frozen and stored at xe2x88x92120xc2x0 C. until used. In the calorimetric DPP-IV assay 5 to 10 xcexcl human plasma and in the fluorometric assay 1.0 xcexcl of human plasma in a total assay volume of 100 xcexcl is used as an enzyme source. The cDNA of the human DPP-IV sequence of amino acid 31- to 766, restricted for the N-terminus and the transmembrane domain, is cloned into pichia pastoris. Human DPP-IV is expressed and purified from the culture medium using conventional column chromatography including size exclusion and anion and cation chromatography. The purity of the final enzyme preparation of Coomassie blue SDS-PAGE is greater than 95%. In the calorimetric DPP-IV assay 20 ng rec.-h DPP-IV and in the fluorometric assay 2 ng rec-h DPP-IV in a total assay volume of 100 xcexcl is used as an enzyme source.
In the fluorogenic assay Ala-Pro-7-amido-4-trifluoromethylcoumarin (Calbiochem No 125510) is used as a substrate. A 20 mM stock solution in 10% DMF/H2O is stored at xe2x88x9220xc2x0 C. until use. In IC50 determinations a final substrate concentration of 50 xcexcM is used. In assays to determine kinetic parameters as Km, Vmax, Ki, the substrate concentration is varied between 10 xcexcM and 500 xcexcM.
In the colorimetric assay H-Ala-Pro-pNA. HCl (Bachem L-1115) is used as a substrate. A 10 mM stock solution in 10% MeOH/H2O is stored at xe2x88x9220xc2x0 C. until use. In IC50 determinations a final substrate concentration of 200 xcexcM is used. In assays to determine kinetic parameters as Km, Vmax, Ki, the substrate concentration is varied between 100 xcexcM and 2000 xcexcM.
Fluorescence is detected in a Perkin Elmer Luminescence Spectrometer LS 50B at an excitation wavelength of 400 nm and an emission wavelength of 505 nm continuously every 15 seconds for 10 to 30 minutes. Initial rate constants are calculated by best fit linear regression.
The absorption of pNA liberated from the calorimetric substrate is detected in a Packard SpectraCount at 405 nM continuously every 2 minutes for 30 to 120 minutes. Initial rate constants are calculated by best fit linear regression.
DPP-IV activity assays are performed in 96 well plates at 37xc2x0 C. in a total assay volume of 100 xcexcl. The assay buffer consists of 50 mM Tris/HCl pH 7.8 containing 0.1 mg/ml BSA and 100 mM NaCl. Test compounds are solved in 100% DMSO, diluted to the desired concentration in 10% DMSO/H2O. The final DMSO concentration in the assay is 1% (v/v).
At this concentration enzyme inactivation by DMSO is  less than 5%. Compounds are with (10 minutes at 37xc2x0 C.) and without preincubation with the enzyme. Enzyme reactions are started with substrate application followed by immediate mixing.
IC50 determinations of test compounds are calculated by non-linear best fit regression of the DPP-IV inhibition of at least 5 different compound concentrations. Kinetic parameters of the enzyme reaction are calculated at at least 5 different substrate concentrations and at least 5 different test compound concentrations.
The preferred compounds of the present invention exhibit IC50 values of 1 nM to 10 xcexcM, more preferably of 1-100 nM, as shown in the following table.
The compounds of formula I and/or their pharmaceutically acceptable salts can be used as medicaments, e.g. in the form of pharmaceutical preparations for enteral, parenteral or topical administration. They can be administered, for example, perorally, e.g. in the form of tablets, coated tablets, dragxc3xa9es, hard and soft gelatine capsules, solutions, emulsions or suspensions, rectally, e.g. in the form of suppositories, parenterally, e.g. in the form of injection solutions or infusion solutions, or topically, e.g. in the form of ointments, creams or oils. Oral administration is preferred.
The production of the pharmaceutical preparations can be effected in a manner which will be familiar to any person skilled in the art by bringing the described compounds of formula I and/or their pharmaceutically acceptable salts, optionally in combination with other therapeutically valuable substances, into a galenical administration form together with suitable, non-toxic, inert, therapeutically compatible solid or liquid carrier materials and, if desired, usual pharmaceutical adjuvants.
Suitable carrier materials are not only inorganic carrier materials, but also organic carrier materials. Thus, for example, lactose, corn starch or derivatives thereof, talc, stearic acid or its salts can be used as carrier materials for tablets, coated tablets, dragxc3xa9es and hard gelatine capsules. Suitable carrier materials for soft gelatine capsules are, for example, vegetable oils, waxes, fats and semi-solid and liquid polyols. Depending on the nature of the active ingredient no carriers might be required for soft gelatine capsules. In this case, the soft gel capsule is considered a carrier. Suitable carrier materials for the production of solutions and syrups are, for example, water, polyols, sucrose, invert sugar and the like. Suitable carrier materials for injection solutions are, for example, water, alcohols, polyols, glycerol and vegetable oils. Suitable carrier materials for suppositories are, for example, natural or hardened oils, waxes, fats and semi-liquid or liquid polyols. Suitable carrier materials for topical preparations are glycerides, semi-synthetic and synthetic glycerides, hydrogenated oils, liquid waxes, liquid paraffins, liquid fatty alcohols, sterols, polyethylene glycols and cellulose derivatives.
Usual stabilizers, preservatives, wetting and emulsifying agents, consistency-improving agents, flavour-improving agents, salts for varying the osmotic pressure, buffer substances, solubilizers, colorants and masking agents and antioxidants come into consideration as pharmaceutical adjuvants.
The dosage of the compounds of formula I can vary within wide limits depending on the disease to be controlled, the age and the individual condition of the patient and the mode of administration, and will, of course, be fitted to the individual requirements in each particular case. For adult patients a daily dosage of about 1 to 1000 mg, especially about 1 to 100 mg, comes into consideration. Depending on severity of the disease and the precise pharmacokinetic profile the compound could be administered with one or several daily dosage units, e.g. in 1 to 3 dosage units.
The pharmaceutical preparations conveniently contain about 1-500 mg, preferably 1-100 mg, of a compound of formula I.
The following Examples serve to illustrate the present invention in more detail. They are, however, not intended to limit its scope in any manner.